This invention relates to a lubricating oil supply controller for a two-cycle engine wherein a lubricating oil can be fed to an intake air passage separately from fuel and without mixing in advance a lubricating oil with fuel which is to be fed to an engine.
In a conventional two-cycle gasoline engine, it is a usual practice that a lubricating oil is mixed with gasoline in advance and thereafter, the lubricating oil is jetted into an intake air passage together with gasoline through a carburetor.
However, if a lubricating oil should be mixed with gasoline, the gasoline which flows through a fuel supply system within the carburetor is reduced to the extent of the amount of lubricating oil mixed therewith. Therefore, in order to compensate for the reduced amount of gasoline, the fuel supply system is required to be formed large.
On the other hand, the carburetor is preferably made somewhat small compared with the engine of a given size and output since in this way, it is easy to supply fuel with proper air fuel ratio in the range from its low speed to high speed driving. As the carburetor becomes large in the size, there is a tendency that the range within which fuel with suitable air fuel ratio can be supplied becomes narrow.
Because of the above reason, another lubricating oil supplier is developed wherein only gasoline is jetted from the carburetor and a lubricating oil is separately delivered into an intake air passage. However, since this supplier is such designed as that the supplying amount of the lubricating oil is in proportion to the number of revolution of an engine, it cannot respond to the supplying amount of gasoline which is supplied in proportion to not only the number of rotation of the engine but also the opening degree of a throttle valve. If the supplying amount of the lubricating oil is set to be that much as to avoid the occurence of the shortage of the lubricating oil in any operating condition, white smoke is likely produced in exhaust gas.
The present invention is accomplished in view of the above.